Springs under turntable


I picked up a set of springs for $35 on Amazon. I intended to use them under a preamp but one thing led to another and I tried them under the turntable. Now, this is no mean feat. It’s a Garrard 401 in a 60pound 50mm slate plinth. The spring device is interesting. It’s sold under the Nobsound brand and is made up of two 45mm wide solid billets of aluminum endcaps with recesses to fit up to seven small springs. It’s very well made. You can add or remove springs depending on the weight distribution. I had to do this with a level and it only took a few minutes. They look good. I did not fit them for floor isolation as I have concrete. I played a few tracks before fitting, and played the same tracks after fitting. Improvement in bass definition, speed, air, inner detail, more space around instruments, nicer timbre and color. Pleasant surprise for little money.
128x128noromance

mitch2

Thanks for the book recommendation....

My best...

The physics is complex yes...

But in a word springs isolate the box from the external vibrations, then there is no more resonance between the 2 speakers in the same room...In my case on the same desk....

Internal resonance are probably less enhanced and decreased without any external influence to amplify them...

This is not the explanation for sure just my 2 cents.... I am not a physicist....

No doubt in my mind that with the right compression applied(i tried 3 rate) it is simple for the ears to discern the best compression , too damping weight on the springs and the sound is warmish or muddy, not enough damping weight and the sound is too bright or too harsh...

Right amount and all is improved on all frequencies...

This is audibly evident.... My ears rarely doubt...Perhaps they are easily deluded but they never doubt... :)
If the speakers are correctly isolated, suspended, then the larger transients that produce energy storage in the cabinets, aught to deform the isolation device through a broad frequency range.

Correctly implemented the high frequencies aught to clean up as does lower frequencies, the cabinet swells and contracts as it will, but relative to the substrate, the goal is to have it’s center of gravity to remain as motionless as possible relative to the substrate.

When correct implementation of zero stiffness on loudspeakers is administered, there is no question of the superiority of this engineering practice on the voicing of the loudspeaker.

Please go ahead and try it, you may just realise a significant bump in performance for what is relatively one of the cheapest upgrades possible.

In correctly isolating using compression springs, (obviously not an issue if hanging from springs), the center of gravity can without a great deal of force, be moved across and outside the base. Short squat sub woofers are much less prone to being knocked over and damaged than speakers where the center of gravity is higher over a narrow base.

The springs themselves, under compression should also have a centralized load bearing low relative to it’s base, unless constrained as in the spring array mentioned above. I generalise that the diameter aught to be close to the final load height of a compression spring for the sake of stability, in this particular use.

The more rigid the substrate, the higher percentage of energies will deform the isolation device, such as a spring. I choose springs because of their broad range of isolation, relatively inexpensive, and easily acquired.
Correct spring rates and geometry are not hard to find, as springs are the most commonly used broad range isolation devices used worldwide.

@mahgister 
I suspect variables related to the success of decoupling speakers include the floor (i.e., concrete or suspended wood), the weight of the speakers, the stiffness and resonant frequency of the speaker box, the force generated by the drivers (i.e., larger woofers create more back pressure than smaller midrange or mid-woofer drivers), whether the speaker design is acoustic suspension or bass reflex, if and how the speakers are mounted on stands, the weight distribution of the speakers (i.e., heavier in the front?), and other variables.
I suspect factors affecting the decoupling medium include stiffness, number of coils, and degree of compression (if using springs), pressure, volume, and elasticity (if using an air bladder), hardness and elastic properties (if using an elastomeric material), and the ability of the medium to decouple in the horizontal plane as well as the vertical plane. 
Manufacturers of things like spring supports, air bladders, and elastic support materials often give weight ranges to help customers select the right product but it would be very difficult to precisely account for all variables.  This may partially account for differences in the degree and types of improvement heard by listeners using decoupling devices.   Since most report hearing positive changes, it is probably a case of close enough being good enough.
lewm, Its okay. I’ve known for quite some time now there are people its just not worth trying to explain anything to. As others have lectured me, its not your forum, you don’t get to tell anyone what to do. On the other foot, the shoe, eh?
Thanks for starting a timely discussion. I put the nobsound springs in my shopping cart last weekend because they looked interesting. I was going to look for reviews, opinions online before pulling the trigger. If there are any left, I'll have to try a few sets!
@mwinkc Try them and report back. I noted one respondent said they heard no difference with the springs under the turntable in their modest system. I wonder is it only noticeable on more resolving systems? I've two more sets coming tomorrow which will allow me to test them under my monoblocks and second turntable. It's going to be a long weekend.
rixthetrick, and on what science to you base this rather floral opinion on? 
Mahgister, I have decided that there is absolutely no way to explain anything with you. You are an inexplicable force of nature. You are however entitled to do anything you want with your system even if it leaves several of us scratching our heads. You are certainly not alone in this regard. Millercarbon comes in a close second. You guys keep us on our toes:)
Mahgister, I have decided that there is absolutely no way to explain anything with you.
The explaining in audio made sense AFTER an experiment....Audio is NOT electronic design only but encompass many fields of science in one game...

Explaining BEFORE an experiment is only most of the times pontificating...

I only want to reach High-End with basic average good elements in a controlled environment.... Is it possible? Yes.....Why ? Audio is more akin to acoustic than to electronics....

My simple concept of the 3 embeddings is my way to describe the conditions we must put in place to reach S.Q.

No sellers will sell you Audiophile experience, you must work, but it is easy when you know the direction to go.....

I am not knowledgeable and hand crafty at all....I was only good in my work to explain books to people....But if i can, anybody can.... But we must be a little creative for sure....

My deepest regards to you....



«  Ears are the sound trying to explain itself»- Groucho Marx


Good noromance. Just don't sneeze:) Lewm is absolutely correct. For a driver to do its job correctly it has to be held rigidly in space. Any spurious vibration of the driver is distortion. The problem really does not become critical until you get down in the bass frequencies. There are several ways of dealing with this. First would be making the cabinet very heavy and stiff. Second would be spiking the cabinet to a very solid floor and third would be using counterforce design with the woofers. Best would be all three together. Putting springs or foam under loudspeakers is 180 degrees the wrong way to go. There is a huge difference in requirement for a device that is designed to pick up vibrations and a device designed to produce them.
Yes!  Increasingly, manufacturers are making enclosures out of aluminum billet.  And then there's granite, Acora reviewed this month in Absolute Sound.  They're designed to stay put.  This is also why front baffles are often heroically over-engineered. And what if the springs themselves start resonating?



@mijostyn - oh yes, you're absolutely correct. And you should totally ignore anything I say unless I can produce a peer reviewed paper on the subject.

You should also ignore isolation devices and stick to your guns.
Cheerio old chap.
@mijostyn, is there any particular thing that I wrote that you question,
or the entirety of my post? I mean if it's only a couple of statements, I might take the time to find evidences, however, you're welcome to dispel and write it off with no further regard.
"When correct implementation of zero stiffness on loudspeakers is administered, there is no question of the superiority of this engineering practice on the voicing of the loudspeaker." (rixthetrick)

rixthetrick, What is zero stiffness? That is a term I have never heard before. How is superior when it comes to "voicing" a loudspeaker. 
They make little blue pills to deal with zero stiffness.......so I’ve been told.
Springs are THE solution for controlling vibration from machinery in commercial applications. I have found these to be more effective in platform applications as compared to ball bearing solutions, which was the case with my Garrard 401, which has its plinth sitting on a platform.
mambacfa, in the case of industrial machinery you are trying to isolate everything else from the vibrating machine. Listening to the machine vibrate is not the objective. I think that is quite different from a device that is intentionally either producing or reading vibration that has to be transferred in an accurate way. The reader has to be protected from all other vibration in the environment and the producer has to be locked in space so that it does not produce any unwanted vibration.

No Flatblackround. I think he is doing cocaine. That produces zero stiffness:)
First, I apologize to Millercarbon for my snotty tone in the context of my reply to his post about springs and such. I find myself in an irritable state of mind probably due to months of isolation and jitters related to the upcoming election. Only my wife can stand to be around me lately.
Second, I must say for the second time that "we" are confusing "vibration" with the pure problem of controlling the motion of a speaker cone. The box has to hold the body of the speaker stable so that the energy generated by the amplifier to move the cone is converted only into motion of the cone. This is never perfectly achieved, of course. My point was that if you put the box on springs or rubbery mounts, then you defeat the effort of the designer to hold the frame or body of the woofer stably in space, while the cone delivers its energy to the air. Instead, the whole assembly is now able to use up amplifier energy in motion that is opposite to the desired application of the force applied to it."Vibration" is certainly a resulting issue associated with the effort to maintain rigidity of the mount, but controlling or dissipating vibrational energy or resonance is after the fact. Do we know of any commercially available speakers that are supplied from the factory with springy or rubbery feet? I cannot think of one.

Picture a naked woofer hanging from a string or springs in mid-air and trying to reproduce a bass tone. Can you see that it would bounce back and forth in directions opposite to the excursions of the cone?
My point was that if you put the box on springs or rubbery mounts, then you defeat
I agree that the speaker has to be fixed. The springs isolate the vibrations from the speaker from exciting the floor - hence the cleaner sound - possibly at the expense of driver fixity. The best sound compromise in this set-up is that the speakers weigh enough to compress the springs such there is little discernible movement AND isolation from the floor is achieved.
The reason why i put 80 pounds of concrete on top of my speakers and it work instead of just using the weight of the speakers only to compress the springs....

Isolation of  2 speakers from one another in the same room is important as much that isolation from other external vibrations...You decrease then mutual resonance amplification...
The springs isolate the vibrations from the speaker from exciting the floor - hence the cleaner sound -
I'd like to see this demonstrated in the laboratory.  Super high-speed cameras and interferometry techniques would do the trick.  If the floor remains static/stable, perhaps it's the speaker enclosure that gets excited.
Guys, I’ve been experimenting with springs in my system for years. I have, maybe, the hardest room type to get great sound out of with it being small and having larger than (I should) speakers in it.

What I’ve done has been a revelation for me. Check out my systems page.

Even within my decoupling platform for my amp/rack, I made an additional platform. The bottom is 3/4" MDF, the top is 3" maple. I recessed the springs into each mating surface at 1/8". The top of the maple platform is recessed to accept 3 halves of Symposium Rollerblock Jrs. The amp mates to the remaining halves. I’m using ceramic ball bearings in the Jrs.

I'm more about experimenting within my room by listening, the old school way.

A good fraction of the energy that causes speaker cabinets to vibrate is coming from the back wave(s) of the drivers in the box, which is an issue separate from holding the drivers stable in position and a reason for the many ported speaker cabinets, which is an attempt to dissipate the sonic energy without exciting the cabinet.  I've always favored Transmission Line woofers, partly for the reason that such designs excite the cabinet very little, resulting in a very clean output.  The only woofers or subwoofers that I have successfully mated with my ESL speakers have been TL types. The cabinets of my home-made TL woofers that I use with Beveridge 2SW speakers are constructed of 1.25" thick HDF and weigh about 100 lbs each.  They don't move.  But given the fact they are TLs to begin with, they aren't very excitable, either.  Maybe this helps explain why I say that there are two separate issues with vibration and resonance.
@mahgister,

I've experimented with weights on top of speakers in the past, not on springs and found that it's easy to overdamp the cabinet. Not always a good thing.
The box has to hold the body of the speaker stable so that the energy generated by the amplifier to move the cone is converted only into motion of the cone. This is never perfectly achieved, of course.
The answer to your question is in the "this is never perfectly achieved"...

There is some critical value where resonance and distortions increase, and a treshold under which the distortions and resonance dont implicate an audible effects...

Putting springs under speakers isolate so much well from the other speakers influence and from feed back effect from the floor and from other external vibrations, then the audible effect is beneficial because the movement of the cone is maintained under a critical threshold...The isolation from external influence is less detrimental to the cone movements than some internal resonance from the speakers box without isolation coming from these external factors ,especially from the other twin speaker in the room...

It is not the case when speakers are not isolated properly.... It is the reason why springs are very useful.... Before i use springs i was using my sandwiches of different materials, that was good damping and complementary coupling and decoupling but not so powerful radical decoupling than springs.....The audible effect was way better than using nothing, but a smearing of the sound subsisted that was erased by the presence of the springs....
I’ve experimented with weights on top of speakers in the past, not on springs and found that it’s easy to overdamp the cabinet. Not always a good thing.
This why God gives me ears: to adjust the weight of the damping mass.... :)

And i use the same ears to adjust the compression of the springs by adding mass to the speakers... It takes me 3 tryings... First not enough: then harshness accent on high frequencies, after that too much weight and darker sound too much accent on the bass or mids bass....

The last one experiment were perfect playing with 2 mass of 5 pounds  ....The critical difference were around adding or substracting 5 pounds of weight on 100 pounds of total mass(speaker mass +concrete slabs)...
@mahgister,

What type of platform are your speaker on and how is it supported?
My springs are on top of this same platform now, where my speakers were before i add springs under them. I keep the"sandwiche" because all my gear are on the same desk....And 2 precautions works better than one.... :)

"Sandwiche" : 4 quartz feet+Granite plate +sorbothane duro 70+granite plate+cork plate+ bamboo plate....I called that a "sandwiche"....

Homemade, peanuts costs and good.... But the springs totally eliminate the residual smearing of the sound...This sandwiche was not completely isolating and the different materials were relatively to some frequencies coupling and not only relatively decoupling, then at the end the S.Q. was way better than nothing, but the addition of springs eliminate much of the unsuspected smearing of the sound at all frequencies....

The acoustic controls of my room do the main job at the end.... And these working of the controls of the room acoustic are way less known than the controls of vibrations and way more important for the final results.... But it is another subject for another thread.... Active acoustic controls and not only passive one....

Controlling vibrations, controlling the electrical noise floor, and controlling the acoustical dimension are what i call controlling the 3 necessary embeddings of any audio system.... :)

Embed everything rightfully before even thinking to upgrade one thing.... :)
You’ve got a lot going on there my friend. Way too much for me to try and analyse. As long as it works for you. Happy listening!

I totally agree on your "three embeddings".
BTW, I bought a set of Connex from 
www.partsconnexion.com years ago. I didn’t like the acrylic, as there was some noise when the springs compressed. Nice to see the Nobsound out of aluminum.

This is why Harbeths and other BBC designs are superior--you don't have to worry about any of this s$!t.
This is why Harbeths and other BBC designs are superior--you don’t have to worry about any of this s$!t.
Ignorance seems to be bliss indeed.... :)

Any speakers need to be isolated even Harbeth , any speakers/room need to be treat and acoustically controlled even with Harbeth speakers in the room,, and all house electrical grid produce noise floor which is too high even those containing Harbeth speakers....

Idolizing a brand name is not a solution to embeddings necessities.... :)

I find it interesting that anytime I interject my experience in a thread, it goes dead. Sorry @noromance .
Lets try to make things simple. Play something with a heavy bass line and put your hand on the speaker/subwoofer. Any vibration you feel is distortion. Ideally you should not feel a thing. If the floor resonates it will do so regardless if the speaker is spiked to it or floating above it on springs. In order to keep the speaker from transferring vibration to the floor the resonance frequency of the suspension would have to be below the lowest note the speakers are to reproduce which means below 20 Hz. Tap your speaker and they will bob for hours. Bring on the damping. Above that frequency the speaker is free to vibrate and add distortion.
Floors are very well fixed in all directions except up and down in the case of wood joist construction. The degree of stiffness varies so every floor has it's distinct resonance frequency. Speakers generally do not point up and down. This is a good reason to avoid down firing subwoofers. You are less likely to excite the floor's resonance frequency. In most cases you are going to be better off fixing the speaker to the floor even if you are not on slab. The best speakers are going to have a very stiff heavy enclosure. 
Okay so the Nobsound springs came and first surprise they are very small and stiff. Tested the full 7 springs with a 10 lb weight and it hardly compressed it. Also the springs fit snug into holes in the top and bottom. They aren't long to begin with and the holes limit the lateral range of motion from the top and bottom coil. Combined with each individual spring being quite stiff and altogether there's hardly any freedom for lateral movement. Nor is there a lot of vertical movement. This explains why the turntable doesn't bounce, twist under torque, etc.

My table https://systems.audiogon.com/systems/8367 altogether with the Shelf is probably a good 50-60 lbs, close to what Nobsound claims is max load (70-80 lbs something like that). After a bit of testing I have removed 3 springs leaving only 4 per unit. The other 12 I will make into four more of 3 springs each to use under my phono stage. Because they do work quite well. Read on.

The Miller Carbon sits on a BDR Source Shelf, with BDR Cones and Round Things between the Shelf and the granite, which in turn sits on a sand bed cast into the top shelf of the solid concrete rack. When the springs go in they replace BDR Cones and Round Things. This is a big deal. The springs are not being compared to any old this or that. People can have their own opinions about BDR. Pretty much always anyone saying anything other than they're excellent you can be sure they never heard them. Would be nice if those eager to criticize my every post would take a moment to include with their response, "Of course he's right, I never heard them." Then go on with the unfounded accusations.

Where was I? Oh yeah. So the springs go in and right away wow this is pretty nice. Very nice.

Did I mention I never did the usual oh we must play this very carefully then play the exact same thing very carefully.... no not at all. Turned the system on, warmed it up, put the springs in, listened to them FIRST. Ha! Because we are millercarbon! (Having fun noromance, this isn't for you, its for them. They know who they are.)

Second track as usual the Koetsu limbers up and smooths out and its sounding really good. Al Stewart is singing and there's a totally seductive palpable feeling of presence that was crazy good before but now is even crazier gooder. Super smooth, yet even more detailed. Like it is hard even to describe as a sound. Its more a feeling than a sound.

Still, it sometimes seems as if there is not quite as much sparkle. Like the extension is there, but... Fortunately the springs are almost exactly the same height as one Round Thing and Cone and so swapping them out is surprisingly easy so out they come and back in goes the BDR. Sure enough, more extension, sharper transients and dynamics. But only on the top end. The midrange just isn't as rich and warm and palpably present any more. Its not even all that close. It reminds me of the difference between analog and good digital, or between tubes and a good solid state amp. Both are good imitations. They sound just fine, until compared side by side and then... sorry but you know what we call second? First place loser.

Nothing chez Miller stays stock for long and so long as they're out a little silicone grease lubes the coils where they sit in the cylinders, and a little fO.q tape goes on top of each set and then back in they go. Can't really say those little tweaks made any improvement but it sure didn't make them any worse, and I'm sure now, the springs are an improvement on BDR.  

I think because everything is sitting on granite which even damped by the sand bed still rings. You can hit it and it makes a very high frequency tink kind of sound. Dies off super fast but its there. Is it a coincidence that this high frequency ringing is close to the range where I was hearing a little less sparkle with the springs? I don't think so. I think the granite was ringing, at a high enough frequency the BDR wasn't damping enough, and so it was getting into and coloring the music. Also these same vibrations were smearing midrange detail. That's why the midrange is now so sexy engaging and real. I mean its not quite liquid lush but compared to most of what's out there it sure is.  

The springs aren't exactly what I would call warm. They strike me as very neutral. But people who actually like digital and solid state might not see things that way. BDR comes in 2 versions, MkIII are a touch warmer than MkIV. The difference is small but its there. The general rule is MkIII for SS, MkIV for tubes. My system being tube/analog is all MkIV. Point being there would probably be even less difference if they were being compared to MkIII.

Been a long time since I got the BDR, 1990's, so kinda forgot but that is probably north of $500 worth of seriously good vibration control bested (if narrowly) by $35 worth of springs.

Good work, noromance!
Congratulations millercarbon....

I own the same set of springs boxes, and the right compression of the springs is very important, i know you know it for sure... i say it for all those who wil buy them....

It takes me 4 trying listening to get it right...

I have around 70 pounds of concrete slabs on top of my speakers, then i think they are pretty optimally compressed with more than 80 pounds on the springs, and when it is right, no defects in the high extension and the bass of my 7 inches drivers is feeled in my chest, the mid frequencies are perfect ....For the turntable it is easy to take off the right amount of springs for the optimal compression...(for my speakers i like them damped ). A variation around 4 of 5 pounds in compressive force is easily audible without problem....

My "sandwichs" of quartz,granite sorbothane, bamboo and cork was great, but when you miss something, you are not always conscious of what you miss, and the sound was smeared not much but enough to create a too much compress mid frequencies and less of extension in the high frequencies and a smeared bass also... .... With the springs smearing of the sound decreased enormously and all is clear but with sweet and warm mid frequencies....

The sound of my Mission speakers is celestial now....They compete the Moabs and i pay them 50 bucks used.... :)

These springs are a bargain....
Most interesting thread, read it all and it stayed 99.9% civil. Excellent considering the subject matter.

So about 6 months ago I experimented with springs under my 401 which is similar to noromance at about 55lb total weight.

There may have been a little more air at the top but to my ears it lost mid and bass impact. Not huge but enough to be noticeable.
Now to be fair these were springs I had bought on eBay after spending a lot of time with a spring calculator trying to make sure I got the best set-up.
Quite possibly I missed the mark.
Those springs are now under a sub.
Just ordered 2 sets of the Nobsound sets off Amazon at $32.99 a set.
These I can tune so now have options.
Many thanks guys!
There may have been a little more air at the top but to my ears it lost mid and bass impact. Not huge but enough to be noticeable.
This is a sign the springs were probably under not enough compression...

It takes me 4 trying to adjust the springs box nobsound....
@mijostyn
"When correct implementation of zero stiffness on loudspeakers is administered, there is no question of the superiority of this engineering practice on the voicing of the loudspeaker." (rixthetrick)

rixthetrick, What is zero stiffness? That is a term I have never heard before. How is superior when it comes to "voicing" a loudspeaker.

My father would have asked me if I'd bothered to look it up, before he'd answer such a complex question.

Zero stiffness:
http://www2.eng.cam.ac.uk/~sdg/preprint/OnZeroStiffness.pdf

As others have already mentioned, the effects of correctly implementing vibration isolation, is audibly heard. Correctly done, it's immediately recognized. And I don't need to prove it, you can do it for yourself, for really cheap. However, you need to know something about what you're doing.

For example the springs in your car/truck/motorcycle are rated specifically for that device. It smooths out the ride, it doesn't completely make it linear. Zero Stiffness is an ideal.

If you have electrostatic speakers (with their own limitations) or dipole speakers (with their own limitations) this is not likely (I would guess) to have nearly as much impact as an enclosure that is ported or sealed.

In most cases, I believe it's not the inertia of the small moving mass of the cone and voice coil that creates the most stored energy in a loudspeaker cabinet. I believe it is the sudden high and low pressure created by the drivers moving air within the cabinet (even a ported cabinet should see this pressure difference) that will deform the walls of the cabinet. It's not just pushing or pulling against the walls, it's doing both at a frequency that excites the cabinet.

Lewm mentioned transmission line woofers, I can see your logic,  and it makes sense. Have you tried isolation anyway?



This is a sign the springs were probably under not enough compression.
I think you could well be right.
When sitting on them they only compressed maybe 1/3 possible not even that.
Hopefully with the adjustment available on the Nobsound springs I can tune it to my liking.
If not I can try them under other items.
In most cases you are going to be better off fixing the speaker to the floor even if you are not on slab.
Okay, enjoy :-)


In most cases you are going to be better off fixing the speaker to the floor even if you are not on slab.
I am afraid that fixing the speaker to the vibrating floor, and letting external vibration in particular of each one of the speaker resonate near one another, will not do the job.... :)
@uberwaltz - I haven't had much success with the cheap Chinese knock-off of the Solid-tech Isoblack, perhaps the Nobosound knock-off is better?

Using the springs you tried earlier, and placed under your sub, you could add mass under your TT with a heavy shelf to try mass loading them?

Are you able to tell me more about the springs under your sub? Wire used, how many turns, spring rate etc?
Rix.
If you had asked when I bought them I would have had all of those answers as I researched it a fair bit.
Tbh now after 9 months or so since purchase I do not have that information to hand or memory... getting old ya know!

Yes I guess I could have mass loaded with something, not that I had or have anything that would likely fit the bill for that purpose lying around.
But worth some pondering for sure.
The adjustment of the compressive rate like you already know is very important....

The nobsound will do the job.... easy to adjust, because a variation around 2 to 5 pounds on the 80/90 pounds of possible compressive weight is very audible....

I use them without any negative effect on all spectrum.... But the adjustment must be done around 3 or4 % of the optimal compressive force.... It is possible the effect even with this little variation in compressive force is very audible....It is way more easy to do with the addition or substraction of slab of 5 pounds each than with the substraction of one or 2 or 3 springs.... :) If you substract one spring on the seven you are left with a ratio of 1/7 , 5 pounds is under this ratio of compressive force, it is around 2 times more refine adjustment than taking off only one spring at a time( 2 five pounds slabs equal roughly one spring if we equal the maximum compressive force around 85 pounds on the 7 springs) ...When i speak of taking off one spring i means in each of the four boxes under each speakers.... :)

I prefer to add weight because i want my speakers damped....
@slaw
I've experimented with weights on top of speakers in the past, not on springs and found that it's easy to overdamp the cabinet. Not always a good thing.
Are you sure by adding the mass, you didn't actually overdamp, but perhaps moved the resonant frequencies into modes that sounded worse?

TMD dampers on top of a loudspeaker cabinet, the likes of the ETI AMG topper. http://www.audiopolitan.com/blog/eti-amg-toppers-review/

I was an employee of the inventor, almost all you need to know what I mean, is found in reading that review.
@rixthetrick,

I've experimented with the Tecknasonic devices years ago on my then, Monitor Audio Studio 20s. Even though those speakers were solid, those devises worked wonders!
@mahgister- I completely agree with you on loading a spring to 3% of its max spring capacity to get the max isolation. I am also working with springs for sometime now. I face two issues when working with springs
1. Spring rate. If you want to get the isolation start around 3-5 cycles for a given load then you have to select springs of very light spring rate. That would lead to using more springs underneath a load and it tends to make the sound harsh, a symptom of ringing...
2. It's important that each spring underneath the load carries equal weight which should be close to 3% of the spring max load bearing capacity. In reality most of the electronics have asymmetrical load and it makes the positioning of these springs difficult underneath a load and very difficult when isolating heavy components like amplifier.
That is why I haven't spent a lot of money in buying a commercial product like Townshend or Solid Tech which would be super expensive yet not solve the 2nd issue.
What I need is a product that would be able to weigh a component and get me the CG location along with its weight distribution in quarters. That would allow me to design & also position the springs underneath any component accurately and w/o any guess work.
Thanks.